Method and apparatus for making bags



M. WAGNER se pzs, 1941.

METHOD AND APPARATUS FOR MAKING BAGS Filed March 19, 1940 2 Sheets-Sheet l Sept. 23, 1941. A M. WAGNER METHOD AND APPARATUS FOR MAKING BAGS llllllllllllllllllllllll 2 Sheets-Sheet 2 Filed March 19, 1940 Patented Sept. 23, 1941 Melvin Wagner, Philadelphia, Pa", assignor to Thomas M.

Royal & Company, Philadelphia,

Pa., a corporation of Pennsylvania Application March 19, 1940,Serial No. 324,894

10 Claims. (Cl-. 9s 35).

This invention relates to new and useful improvements in methods and apparatus for making bags. The invention relates more particularly to a method and apparatus for making multiple ply bags having bellows-folded side walls, all seams of which are formed by the fusion ofsurfaces of the inner ply to each other, and is a continuatlon'in part of my application Serial No. 283,275, filed July 7, 1939, which application is a division of application Serial No. 237,736, filed October 29, 1938.

During the past year or so the bag industry has given particular attention to the sealing or securing of the seams and bottoms of bags by the application of heat to effect a fusion of the surfaces of the bag material in desired regions or areas, and such methods have proven highly satisfactory in the case of bags of the type of the so-called fiat bag which has no reentrant folds. In the case of multi-ply bags havingso-called bellows-folded side walls, this method of sealing the bottoms of such bags has been wholly unsucillustrating the method by which the bag shown in Figures 1 and 2 may be manufactured.

Figure 4 is an enlarged view in section taken on line 4-4, Figure 3.

Figure 5 is an enlarged fragmentary view in section taken on line 5 5, Figure 3. Figure 6 Ba fragmentary view in perspective illustrating a manner in whichthe heat-sealed bottom or top end of the bag may be foldably manipulated.

Figure 7 is a diagrammatic fragmentary view in perspective of certain modifications of the method disclosed in Figure 3. v

Figure 8 is an enlarged view in section taken on line 8-8, Figure 7; and

Figure 9 (is an enlarged fragmentary view in section takenon line 99,.Figure 7.

cessful due to the fact that the bellows side walls, being reentrant folds, introduce the outer ply or I plies of material between opposite surfaces of the innermost fusible or thermoplastic ply thus causing a" gap or pin hole to occur in the opposite interior wall surfaces at the termination of these reentrant or bellows-folded portions and making it impossible to obtain a tight end joint.

With the foregoing in mind, the principal object of the present invention is to provide a satisfactory and efficient method and apparatus for making a bellows-folded multi-ply bag wherein all of the seam are secured by fusion of the innermost ply.

Another object of the present invention is to. a

provide a method and apparatus for making a bag of the type described wherein the introduction of the outer plies between opposite faces of the inner ply at the end joint of the bag'is prevented.

Referring now more particularly to Figure 3 folded reentrant portions in the region of the These and other objects of the'invention and the features and details of the construction and manufacture thereof are hereinafter fully set forth and shown in. the accompanying drawings,

in which:

Figure 1 is a view in perspective of a multl-ply baghaving bellows-folded side walls made according tothe present invention.

Figure2 is a fragmentary view in perspective showing'such a bag open with the bellows side walls in expanded relation.

Figure 3 is a diagrammatic view in perspective formed. I I

After the formation of the openings 5 as above bottom or p end joint area of the bag to be described, a web 6 of heat-fusible or thermoplastic material, such as fPliofilm, or the like, of width form a tube having reentrant or bellows-folded side walls with the opposite edge portions of the web 6 in overlapping relation along the upper side or face of said tube.

The tube then passes between one or more pairs of press rolls I and I I and then beneath a longitudinally extending heating iron or element I3 which is arranged so as to overlie the lapped seam portions thereof.

The iron or element I3 may be heated in any suitable manner such generated therein penetrates through the backing web I to cause a permanent fusion of the overlapped edge portions of the heat-fusible or thermoplastic inner web 6 as indicated at A in Figure 1 of the drawings. The thus longitudinally sealed tube next passes between a pair of rolls I4 and IS, the roll ll of which carries a cutting knife or blade I6 arranged and operable to sever sections from the tube along lines coincident with the transverse axes of each pair of the now covered openings previously described.

The longitudinally sealed tube sections then pass beneath one or more rolls I1 and into a bottom end sealing mechanism which is arranged so as to grip or clamp the leading edge portion of each tube section at or prior to the instant it is severed from the tube. A number ofgrips or clamps I8 are provided and several of'these move through the end sealing mechanism in engagement with each tube section which are sup ported upon a moving endless belt I9. In addition to the grips or clamps I8 several transverse heating irons or elements 20 are associated therewith, and these are arranged with respect to said grips or clamps I8 so as to engage the rear edge portion of each tube section during travel thereof through this mechanism, the heat from said iron or element 20 penetrating the several layers of material of the composite web to effect a permanent fusion of the adjacent surfaces of the underlying portions of the inner ply of heat-fusible or thermoplastic material as indicated at B in Figure 1 of the drawings.

A modification of the foregoing -method is shown in Figures '1, 8 and 9 of the drawings wherein, in forming the tubeabout the former 9, the opposite edge portions of the heat-fusible inner web 6 are first brought into overlapping relation along the upper side of the tube and heatsealed together before lapping thereover the edge portions of the paper outer ply I. plished by interposing a heating iron or element Illa between the edgeportions of the paper outer ply I as shown in Figure 8 and said heating element Ifla is thus afforded direct contact with the lapped edge seam portions of the heat-fusible inner ply 6.

The reason for adopting this modification resides in the fact that when the inner ply seam is fused by the application of heat theretothrough the outer paper ply I as first described, the heating iron IIIa under which the completely seamed tube is' drawn very often leaves a dark brownish line or lines along the surface of the outer paper ply where contacted by said iron. These lines disfigure and detract substantially from the appearance of the completed bags and I have found that the occurrence thereof may be eliminated entirely and an equally effective inner ply seam produced by this method of heat-sealing said inner ply seam prior to lapping thereover the edge portions of the paper outer ply I.

After sealing the inner ply seam in accordance with this modification,

as electricity and the heat This is accom-- the tube then passes be-.

tween a pair of rolls 2| and 22 which operate to bring the edge portions of the outer paper pit or web I into lapped relation in which relation they are secured by means of adhesive previously applied to the inner surface of the overlapping edge portion of said web I as indicated at 23. The thus longitudinally sealed tube next passes between a pair of rolls Ila) and lid, which carries a blade Iia arranged and operable to sever sectionsfrom the tube along lines coincident withthe transverse axes of each pair of the now covered openings 5 previously des'cribed.

The resulting tube sections then successively pass into a bottom end sealing" device or mechanism which, in the present modification of the invention, comprises a number of grip elements I8a arranged to move in cooperative opposing engagement with each of the tube sections, and in addition to these grips I8a, cooperatively opposed heating elements 20a are associated therewith and arranged with respect thereto to engage from opposite sides of the leading edge portion of each tube section and travel therewith through said mechanism, the heat from said elements 200 penetrating the several thicknesses of the sections to effect a permanent mediate portions of the heat-fusible inner ply 6 as indicated at B in Figure 7 of the drawings.

It will be observed from the foregoing description that by forming the openings 5 in the web I in the manner and at the locations previously described none of the backing or material of said web I is introduced between the reentrant folds and web material 6 at the bottom end of the tube or bag thus eliminating thepossible occurrence of gaps or holes in the interior wall surfaces at the termination of such reentrant or bellows-folded portions at and adjacent the bottom end of the bag, and making it possible to obtain and secure a tight end joint at the bag bottom. The particular arrangement of the openings 5 in the web I also removes the material of that web from the reentrant folds and surfaces of the heat-fusible web 6 at the top open end of the bag, and

this is done so that after the bag has been filled permitting a tight closure to be obtained for the same reasons set forth above in connection with the fusion of the bottom end of said bag. After fusion of the bottom end of the bags according to either of the foregoing methods they are discharged from the bottom sealing mechanism at which time their bottom end portions may, if desired, be foldably manipulated and secured by means of adhesive in the relation shown in Figure 6 of the drawings. This same thing may, of course, be done with the top end of the bag after it is filled and heat-sealed in the mannerpreviously described.

From the foregoing it will be seen that the present invention provides a novel method and apparatus for making a bag of the reentrant belthe former of fusion of the intersurfaces of the heat-fusible or thermoplastic the top of the bag opposite surfaces of the of said backing material portion of' said paper outer web lapped edge portions of the thermoplastic inner web, applying heat directly to saidlapped edge material to fuse 4 paper outer web tion with respect to the inner 2. In the method of making multi-ply bags,

transversely spaced of said paper outer respect to the inner trant bellows-folded side tion of the paper outer web is deflected, lapping and securing together the edge portions of the paper outer web in overlying relation with respect to the'inner web, cutting bag sections from the tube transversely thereof along the transfaces of the adjacent portions of the thermoplastic inner ply.

4. In the method of making multi-ply bags,-

the steps comprising forming transversely spaced pairs of openings in a web of paper at predetermined intervals therealong, duplexing a web of thermoplastic material on said paper web, forming the duplex web into tubular form with reentrant bellows-folded. side walls which include the transversely spaced pairs of openings in the paper web, the said tubular form having the therpaper outer web is and securing together the opposite edge portions web.

6. In the method the steps comprising duplexing a web or paper and aweb of thermoplastic material, forming the thermoplastic material on said paper web, iorming the duplex web into tubular form with reens Y web in overlying relation with of making multi-ply bags,

duplex web into tubular form with the thermoplastic web residing interiorly with its edge portions extending longitudinally in lapped relation beneath an overlying edge portion of the outer paper web, deflecting said overlying edge portion of the paper outer web away from the inner thermoplastic web, applying heat directly to said lapped edge portions of said thermoplastic web to fuse the same together while the overlying edge portion of the paper outer web is deflected, returning the deflected edge portion of the paper outer web to its position overlying the fused lapped edge portions of the thermoplastic inner web, and then lapping and securing together the opposite edge portions of said paper outer web in overlying relation with respect to the inner web.

7. Apparatus for making multi-ply bags comprising means for feeding and duplexing a web of paper and a web of thermoplastic material, means for forming said duplex web into tubular form with the thermoplastic web residing in teriorly with its edge portions extending longitudinally in lapped relation beneath an overlying edge portion of the outer paper web, a member interposed between the lapped edge portions of the inner thermoplastic web and the overlying edge portion of the outer paper web for deflecting said edge portion of the paper web away from said lapped edge portions of the thermoplastic web, and a heating element carried by said member and arranged to apply heat directly to the lapped edge portions of said thermoplastic web to seal the same together while said overlying edge portion of the outer paper web is deflected by the member.

8. Apparatus for making multi-ply bags comprising means for feeding and duplexing a web of paper and a web of thermoplastic material, means for forming said duplex web into tubular form with the thermoplastic web residing interiorly with its edge portions extending longitudinally in lapped relation beneath an overlying edge portion of the outer paper web, a member interposed between the lapped the inner thermoplastic web and the overlying edge portion of the outer paper web for deflecting said edge portion of the paper web away from said lapped edge portions of the thermoedge portions of lapped edge portions gether theopposing surface portions of moplastic inner web.-

moplastic material, means for forming said duplex web into tubular form with reentrant' bellows folded side walls which include said transversely spaced pairs of openings in the P p r web and with the thermoplastic web residing interiorly with its edge portions extending longitudinally in lapped relation beneath an overlying edge portion of the outer paper web, a member interposed between the lapped edge portions of the inner thermoplastic .web and the overlying edge portion of the outer paper web for deflecting said edge portion of the paper web from said of the thermoplastic web, a heating element carried by said member and arranged to apply heat directly to the lapped edge portions of said thermoplastic web to seal the same together while said overlying edge portion of the outer paper web is deflected by the member, means for cutting bag tube transversely thereof on a line through the openings in the outer paper web, and means disposed beyond said cutting means for applying heat transversely of said bag sections at one end thereof on a line through said openings to seal tothe ther- 10. Apparatus for making multi-ply bags comprising means for advancing a web of paper and plastic web, a heating element carried by said said inner thermoplastic web.

9. Apparatus for making multi-ply bags comprising means for advancing a web of paper and a web of thermoplastic material, means for forming transversely spaced pairs of openings in said paper web at predetermined intervals therealong, means for duplexing the webs of paper and therplex web a web of thermoplastic material, means for forming transversely spaced pairs of openings in said paper web at predetermined intervals therealong, means for duplexing the webs of paper and thermoplastic material, means forforming said duinto tubular form withreentrant bellows folded side walls which include said transversely spaced pairs of openings in the paper web and with the thermoplastic web residing interiorly with its edge portions extending longitudinally in lapped relation beneath an overlying edge portion of the outer paper web, a member interposed between the lapped edge portions of the inner thermoplastic web and the over ying edge portion of the outer paper web for deflecting said edge portion of the paperjweb from said lapped edge portions of the thermoplastic web, a heating element carried by said member and arranged to apply heat directly to the lapped edge portions of said thermoplastic web to seal the same together while said overlying edge portion of the outer paper web is deflected by the member, means for positioning the edge portions of the outer paper web in lapped relation over- MELVIN WAGNER.

sections from the 

